Pulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).ulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).
The area of the World Ocean is about 361.9 million square kilometers (139.7 million square miles), which covers about 70.9% of Earth's surface, and its volume is approximately 1.335 billion cubic kilometers (320.3 million cubic miles).
The Earth's atmosphere is ideal for supporting life. Most of the Earth's surface is covered with water. From the sky, the Earth appears blue. Earth is the only inner planet in our solar system that has liquid water on its surface. Seventy percent of the Earth's surface is covered with water. Mountains, volcanoes, deserts, plains, and valleys cover the remaining 30 percent. Earth has an atmosphere made up of many different gases.